Log1ned, да не стоит смотреть на модели. Все контроллеры одной ценовой категории - равны. Иначе бы их не покупали поставщики. Точно хочешь 25 keys? будет мало, если начнёшь в серьёз учиться.

А на счёт выбора, зависит от того что ищешь. Для качества, если бы я занимался этим профессионально, я бы точно взял PRO серию M-audio.

Существуют модели,
M-Audio Axiom 25 (~179$)
и
M-Audio Axiom Pro 25 (~400$)

Платишь лишние 200$, только за Advanced HyperControl technology

Enhanced DAW Integration with HyperControl Technology
Thanks to revolutionary M-Audio HyperControl technology, your Axiom Pro 25 controller will automatically map to commonly used parameters of popular software instruments and digital audio workstations including Pro Tools, Cubase, Logic and Reason* systems. HyperControl updates the virtual instrument or track parameter mappings of each control in real time as you sequence--it doesn't get any easier.

The HyperControl Difference
While other controllers offer mapping, only the M-Audio Axiom Pro line has HyperControl technology. HyperControl synchronizes Axiom Pro with your DAW, ensuring that your hardware and software collaborate to form a single work environment. The technology utilizes the Axiom Pro 25 graphic LCD to group software controls together in a modular fashion. Similar controls are organized in named groups and accessed via four dedicated softkeys, which are continually updated to reflect the mapped parameters. A dedicated button toggles between Mixer and Instrument modes for instant hands-on control of all of your software's functionality. Dedicated Track buttons allow sequential navigation of your mixer and instantaneous mapping of software instruments within the selected track. You can even control software instruments without opening them.